Coal-drill.



D. S. BACHELDER..

COAL DRILL.

APPLICATION FILED m1; l9, I916.

1,251,323. mm ne. 25,1 17;

ture opens.

UNITED STATES PATENT OFFICE.

DAVID S. BACHELDER, OF TILDEN, ILLINOIS, ASSIGNOR 0F ONE-HALF TO JAMESCONNOR, OI TILDEN, ILLINOIS.

COAL-DRILL.

ran ed that the chips or bits of coal or rockas t ey are cut from thebed are guickly removetffrom the bore which the rill struc- With thisobject in view the drill com-, prises a head having at one end a socketby means of which it maybe attached to a drill rod in a usual manner;the said head having atits other end portion openings one positioned atthe center of the head and adapted to receive thecenter drill bit andthe other openings arranged. one at 'each side of the said centralopeningand adapted to receive the shank of the side'drill bits. The saidhead is provided at its'exterior with spirally disposed spaced ribs theouter edges of which are relatively sharp and the head between the saidribs is curvedor concaved thereby eliminating angles and sharp cornerswhich would interfere with the free 'passag'eof the drills dust alongthe said ribs as the said material is being forced from the bore whichis opened by the drill structure. The side drill bits have their outeror forward end portions spiral twisted to conform substantially with thespiral disposition or twist of the ribs located at the exterior of thehead and the said side drill bits are provided at their forward endswith cutting edges which are substantially radially disposed withrelation to the axis of the head.

In the accompanying drawing d 1 is a side elevation of the coal Fig. 2is a longitudinal sectional view of the same;

Fi 3 is a similar view out on a plane at a rig t angle to that on whichthe section of 2 is cut;

ig. 4 is a transverse sectional view out on the line 4-4 of Fig. 1;

'" Specification of Letters Patent. Patented Deb. 25,1917.

Application and April 19, 1916. Serial No. 92,191.

Fig. 5 is a similar view out on the line 5 -5otFig.1. i The coal drillcomprises a head 1 having at one end a socket 2 adapted to receive a rodwhereby the said head may be rotated in a usual manner. Any suitablemeans may be provided for securing the head upon the rod in a mannerwhich will permit the head to be removed from the rod when desired.

The head 1 is provided at its forward end with a central non-circularopening 3, the inner end of which communicates with the inner end of thesocket 2. A center drill bit 4 is provided with a shank 5 which fitssnuglyin the opening 3 and a set screw 6 passes transversely through theside of the head 1 and bears at its inner end against the side of theshank 5 and serves as means for .detachably holding the bit 4 in theopening 'gular or non-circulanin transverse -section. Side drill bits.10 are )rovided with non-circular shanks 11 w ich fit snugly in theopenings '8 and the inner ends of the said shanks 11 are receivedin theslots 9. The outer portions of the side drill bits 10 are spirallytwisted as at 12 and the said bits 10 are provided at their outer or.forward ends with cutting edges 13 wh. -h are disposed approximatelyradially with relation to the axis of the head 1 and at acute angleswith relation to the said axis. Set screws 14 pass through the head '1and hear at their inner ends against the shank 95 11 of the side bit 10and serve as means for detachably holding he shanks in the openbetweenthe said ribs 15 is concaved or curved whereby the head 1 between thesaid ribs 15 is devoid of sharp corners or angles which would interferewith the passage of material through the space between the ad'- jacentribs 15.

In operation the center drill bit 4 is positionedagainst relativelyhardmaterial as for instance rock or slate and. the head 1 is The centerrotated in the usual manner. drill bit 4: penetrates into thesaid hardmaterial and the chips or dust cut by the bit 4 is taken up by thetwisted portions 12 ofthe side drill bit 10 and moved into the spacesbetween the ribs 15 which in turn operate upon thesaid material to'workthe sametoward that end of the head 1 which is connected with the rodwhich operates the same at the socket 2.

In view of the fact that the ribs 15 are sharp at-their outer edges andthe head 1 between the ribs isdevoid of an les or sharp corners thereare'no spaces in w ich the fine material may accumulate and interferewith the operation of the drill or the, free passage, of the chips fromthe bore which is being cut by the drill. a

Following the bit 4' the cutting edges 13 of the side drill bits 10enter thematerial.

and enlarge the bore and thechips which are cut from the solid rock orcoal by the cutting-edges 13 of the sidebits 10 are moved along thetwisted portions of the said side bits 10 and pass into the spacesbetween the ribs 15 which in turn operate upon the said material to moveit alon the head 1 and -eject it-from the head at the ends thereof whichis provided with the socket 2.

VV hen 1t isdesired to sharpenthe bits 4 and 10. or to renew the samethe set" screw .6 is removed from the head 10 whereb the bit 4 may beslipped out of the openlng3 and the set screws 14' are removed fromagainst the shankll whereby the bits 10 may be remoi'ed from theopenings 8. ,In the event that the shanks 11 stick in the openings 8 animplement may be inserted through the slots 9 and against the inner endsof the/said shanks for forcing the shanks out-of the openings 8.

With the drill, such as described herein, it is found the coal and ballsof sulfur lodged therein are out very rapidly and evenly and the speedat which the hole is formed correspondinglfi' increased. At the sametime, it is foundt at the drill turns very lightly and conjunction withthe accompanyin the removal of particles of dust from the hole andthereby prevent interference to' the proper operation of the drill fromthis cause.

Furthermore the material of. which the head is composed is so disposedabout the open--- ings 8 that-the presence of the said openin doesnotweaken t'he'head hence they may extended for a considerable distancein the head and in view of the fact that they are comparatively long,they may retain drill bits having long shanks. Thesebits having longshanks are susceptible of being sharpened many times before their shanksare ren dered too .short to be securely held in the o enin Thesharpening of the bits is e ecte .by flattening portions of their shankson the horn-of an anvil, and peening down their cutting edges "with ahammer. Hence the bits may be-kept in proper condition without the useof special or expensive sharpenin machines or devices. 7 i 'From t eforegoing description taken in drawing it will be seen that a coal drill0 sim 1e and durable structure is provided and t at" the. same willefiiciently operate to operi 1a 5 I bore "in solid-goal or rock andremove the chips or cut material from the said bore promptly during theoperation of forming the bore in the said solid material.

Havin claimed 1s:-'--' t I A drill comprising ahead provided withopenings which extend longitudinally of the head and parallel therewithand adapted to receivedrill bits, said openings at their inner endsterminating in slots. which open at the sides of the head, 'spaced ribsacuminatedin' transverse section and spirally disposed along theperiphery of the head at the opposite edges of the slots, the surfacesof the material of the head between the ribs being concavedly curvedlongitudinally of the head and (wnvexedly curved transversely thereoffrom edge to edge of the adjacent ribs and the said surfacesintersecting each other at the keen edges of the ribs.

In testimony whereof I aflix my signature.

DAVID s. BACHELDER.

described the invention what is head at the opposite sides of the axisof the

